--- a/devtools/client/netmonitor/src/request-list-context-menu.js
+++ b/devtools/client/netmonitor/src/request-list-context-menu.js
@@ -18,16 +18,17 @@ const {
   getSelectedRequest,
   getSortedRequests,
 } = require("./selectors/index");
 const { L10N } = require("./utils/l10n");
 const { showMenu } = require("./utils/menu");
 const {
   getUrlQuery,
   parseQueryString,
+  getUrlBaseName,
 } = require("./utils/request-utils");
 
 function RequestListContextMenu({
   cloneSelectedRequest,
   openStatistics,
 }) {
   this.cloneSelectedRequest = cloneSelectedRequest;
   this.openStatistics = openStatistics;
@@ -304,17 +305,17 @@ RequestListContextMenu.prototype = {
     copyString(this.selectedRequest.responseContentDataUri);
   },
 
   /**
    * Save image as.
    */
   saveImageAs() {
     let { encoding, text } = this.selectedRequest.responseContent.content;
-    let fileName = this.selectedRequest.urlDetails.baseNameWithQuery;
+    let fileName = getUrlBaseName(this.selectedRequest.url);
     let data;
     if (encoding === "base64") {
       let decoded = atob(text);
       data = new Uint8Array(decoded.length);
       for (let i = 0; i < decoded.length; ++i) {
         data[i] = decoded.charCodeAt(i);
       }
     } else {